Thermal tolerances of the Caribbean sea urchins Eucidaris tribuloides, Echinometra lividis, and Echinometra lucunter (Echinodermata: Echinoidea): Potential impacts of climate change

With warming oceans, the physiological functions of organisms may be altered due to thermal stress. The sea urchins Eucidaris tribuloides and Echinometra lucunter are both ecosystem engineers in their respective environments. Understanding how these species will be impacted by thermal stress will lead to a better understanding of the affects they will have on their ecosystems. A laboratory study was conducted to establish the feeding rates and behaviors of E. tribuloides and E. lucunter at 26C, 29C, 32C and 35C. A field study was conducted to observe at which temperatures E. tribuloides and E. lucunter were found. There were no significant differences in feeding rates at different temperatures for E. lucunter or E. tribuloides (p=0.301). Similarly, there were no differences in activity coefficients for individuals which righted themselves when placed on their aboral surface (p=0.299). There was a significant decline in the number of E. tribuloides able to right themselves at higher temperatures (p= 0.01232), but not of E. lucunter (p=0.5983). Eucidaris tribuloides showed a distinct association with rubble with fleshy algae and at a temperature of 26C(p=0.001), which E.viridis did not. This information will aid in understanding how sea urchins may impact their natural habitats in response to anticipated ocean warming.